In the past, turntables for record players and the like have been coated with flock, felt or other fiberous matter to retain the record disk in position while the pickup tone arm and the needle traversed the disk and reproduced the sound through one or more amplifiers and speakers. As the record player equipment became more sophisticated and more sensitive, acoustical and mechanical feedback became evident and it was determined that at least a portion of the feedback was the result of slight movement of the record disk relative to the turntable.
Some efforts were made to hold the record disk in fixed position and these efforts included the evacuation of air from the bottom of the record disk so that atmospheric pressure would apply a downward force on the disk to hold the disk in fixed position on the turntable. However, most of these efforts caused the evacuation of air from below the record disk and therefore, could not be readily applied to existing record playing equipment. Some examples of this type of structure are shown in U.S. patents to Manwaring U.S. Pat. No. 793,140; Aylsworth U.S. Pat. No. 1,062,579; Rabinow U.S. Pat. No. 3,608,909; and Doughty U.S. Pat. No. 4,065,135.
Other efforts to hold the disk in position included the placing of a weight or the like on top of the record disk to hold the disk in position. Some examples of this type of structure are shown in U.S. patents to Zimmerman U.S. Pat. No. 2,146,519 and Camerick et al U.S. Pat. No. 3,980,308.